/**
 * Copyright 2010 Nicholas Alexander Cross
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.dataporter.io;

import org.apache.commons.lang.NullArgumentException;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.Map;

public class FileEntitySink implements EntitySink<OutputStream> {

    private final File outputLocation;
    private final Map<String, String> filenameMappings;

    public FileEntitySink( File outputLocation, Map<String, String> filenameMappings ) {
        this.outputLocation = outputLocation;
        this.filenameMappings = filenameMappings;

        if ( outputLocation == null )
        {
            throw new NullArgumentException( "outputLocation" );
        }
    }

    public FileEntitySink( File outputLocation ) {
        this( outputLocation, null );
    }

    public OutputStream sinkForEntity( String entityName ) {
        try
        {
            return new FileOutputStream( new File( outputLocation, filenameForEntity( entityName ) ) );
        }
        catch ( FileNotFoundException e )
        {
            throw new IllegalStateException( "Cannot create output sink stream", e );
        }
    }

    /**
     * Can be overridden if the default name is not good enough
     *
     * @param entityName
     * @return
     */
    protected String filenameForEntity( String entityName ) {

        if ( filenameMappings != null )
        {
            String filename = filenameMappings.get( entityName );

            if ( filename == null )
            {
                throw new IllegalStateException( "No filename mapping for entity: " + entityName );
            }

            return filename;
        }

        return entityName.toLowerCase() + ".csv";
    }


}
